# Higgs boson only interacts with accelerating particles?

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1. Jan 16, 2012

### junglebeast

What is the fundamental rationale for why particles moving through the Higgs ocean would only interact if they are accelerating?

2. Jan 16, 2012

### kurros

Well, no, the Higgs field interacts with particles whether they are accelerating or not. You don't have to accelerate to have mass. Sure, you can't tell that you have mass until some acceleration happens (unless you are large enough to gravitate measurably), but that doesn't mean that you don't have mass.

3. Jan 16, 2012

### junglebeast

Well, from the definition, mass is precisely the resistance to acceleration:

Furthermore, according to Briane Greene, who arguably knows what he is talking about, the resistance of inertia/mass is due to interactions of quarks and electrons with the Higgs ocean that only occur when objects try to accelerate,

Thus, I repeat the question: why is it that Higgs boson only interacts with particles that try to accelerate through the field, and does not interact with particles that move through the field with constant velocity?

4. Jan 16, 2012

### DaveC426913

While they may be proportional, that does not mean mass is nothing more than the resistance to acceleration.

For example a stationary object undergoing no acceleration still has mass, as evidenced by the curvature it imbues to space.

5. Jan 16, 2012

### kurros

Yes, but just because you are not currently resisting acceleration does not mean that you have no mass. It is F=ma. If a=0, then yes of course F=0, but that in no way implies that m=0 also.

6. Jan 16, 2012

### DaveC426913

Or that, yeah.

7. Jan 16, 2012

### junglebeast

I'm not the one claiming that:
a) "the Higgs field is responsible for giving mass to particles"
b) "it does so by interacting with particles that are accelerating."

...I'm simply asking for explanation of these (seemingly well-accepted) claims of modern physics.

Last edited: Jan 16, 2012
8. Jan 16, 2012

### DaveC426913

I don't believe this one is true.

9. Jan 16, 2012

### junglebeast

An object that is falling towards Earth is clearly accelerating relative to the reference frame of some point on the surface of Earth. However, I think that according to general relativity, it is not actually accelerating relative to the reference frame of absolute spacetime. In other words, I think that if you take into account general relativity, then inertia and mass may become synonymous.

This would imply that, when it is claimed that Higgs particles only resist accelerations, it means that they only resist accelerations relative to the absolute spacetime of general relativity (as opposed to resisting accelerations relative to other objects in spacetime).

10. Jan 16, 2012

### junglebeast

Inertia is resistance to acceleration.
Inertia is at least proportional to mass.
The Higgs ocean is claimed to hinder the movement of certain particles by interacting with them.
Thus, based on these facts alone, we are forced to conclude that the Higgs interactions only occur for accelerating particles...so if you disagree with that point, it must be that you also fundamentally disagree with one of the first three points.

11. Jan 16, 2012

### 6.28318531

Your first two points are fine, the third one however you seem to be confusing what the Higgs mechanism does. The Higgs field that permeates space gives inertial mass to particles. Mass would be like an objects resistance to change in speed, but this doesn't imply that Higgs interaction only occurs for accelerating particles. Higgs gives the particles mass, and inertial mass is what resists acceleration.

12. Jan 16, 2012

### maverick_starstrider

I really don't think this is as abstract as you're making it out to be. In quantum field theory, if you add in a Higgs field and solve for the equations of motion you get corrections relative to the equations of motion had you not included a Higgs field. These corrections have precisely the form of particles with mass. Actually the real mechanism of the Higgs mechanism is really far too abstract to get anything from a Briane Greene book (though that's probably true for everything in physics, the point of popular science isn't actually to convey understanding, just generate excitement and share results). If I remember my QFT correctly (which I may not be), the simplest way the Higgs mechanism manifests is by showing how a scalar (light-like if you want) field acquires apparent mass and a third polarization.

13. Jan 16, 2012

### maverick_starstrider

This whole picture of the Higgs field as a "resistance" is really quite flawed, it's just an analogy they came up with for conveying pop science. I wouldn't take it too seriously. The Higgs mechanism ISN'T a drag, I don't know about you but I've never seen an equation for drag that was Lorentz Invariant. You really can't port over intuitions like that

14. Jan 16, 2012

### junglebeast

Mass is a property that assists in describing the behavior of the particle. Like all properties, it is either a fundamental property, or it is a derived property. If it is a fundamental property, then by definition, nothing can possibly "give" or "explain" this property because it is a core axiom of the physical laws that this property is true.

The Higgs field theory is necessarily a theory that mass is a derived property, meaning that there is some lower-level physical process that explains why we should expect the mass-based equations to be [approximately] correct without invoking the concept of mass. Obviously, there must be some kind of mathematical explanation of this sort -- otherwise, nobody would be discussing the concept of such a hypothetical unobserved particle. Thus, your literal statement that "Higgs gives mass", without discussing the interactions of the Higgs particle, is purely nonsensical.

Field equations are merely a method for analytically calculating the results of a system containing interactions that are more complex and would otherwise require simulation to obtain. For example, the EM field equations are a simplification that do not mention the fact that the actual force of the field is carried by virtual photons that are created and absorbed under the uncertainty principle in a way that transmits momentum from one electrically charged particle to another. If one is after an understanding of the physical process, the field equations are entirely irrelevent; likewise, if one is after a practical calculation, the low-level physical explanation is irrelevent. In this case, because I am not trying to perform a specific calculation, the Higgs field equations corrections are irrelevent to the discussion: only a discussion of the physical interaction behind those equations is relevant.

Yes, there is a physical explanation. Under the wikipedia entry for Higgs mechanism, it does say that "The simplest implementation of the mechanism adds an extra Higgs field to the gauge theory," and then goes onto explain somewhat of the more detailed physical explanation: "The particles gain mass by interacting with the Higgs field that permeates all space. More precisely, the Higgs mechanism endows gauge bosons in a gauge theory with mass through absorption of Nambu-Goldstone bosons arising in spontaneous symmetry breaking."

Obviously he is leaving out details, but that does not mean that the things he is saying are completely false. When somebody says "the Higgs ocean is made up of particles that interact with quarks and electrons" this is not simply a metaphor for, "There is a differential equation that makes no reference to interactions or quarks or electrons", as you suggest. In fact, the Wikipedia entry definitely confirms that what Brian Green said is true yet lacking in details, as one would expect. If you do not know these physical details, simply do not answer pretending like you do know. It is only more confusing to me to have answers from people who clearly do not have a complete grasp of the subject, and make statements that directly contradict the statements of respected physicists such as Greene, who's statements are corroborated by wikipedia, and apparently, a lot of other references.

15. Jan 17, 2012

### 6.28318531

Clearly Greene is trying to introduce the concept in a way that the layman will understand, this is not what everyone is opposed to. You claim however

16. Jan 17, 2012

### LBloom

You have clearly misread what Brian Greene wrote. Nothing anyone has said here contradicts Brian Greene. The Higgs field is what is responsible for giving particles mass. Excitations of this field gives rise to particles called the Higgs Boson, in much the same way that the electromagnetic field gives rise to excitations called photons. The ocean filled with particles is just a metaphor for this.

The Higgs field interacts with certain particles and gives them mass. It interacts with particles whether they are accelerating or moving at a constant velocity (and hence at rest in their own reference frame).

A particle has mass regardless of whether it is accelerating or not. If it has mass when it is at rest, then the Higgs field must be interacting with it, so obviously the Higgs field interacts with particles at rest. If the particle were massless it would be moving at the speed of light!

Go back and either try to reread Brian Greene's book or take some time and learn QFT. You can't learn physics without the math. Pure physical reasoning will lead to faulty conclusions because you may be thinking too classically about a quantum phenomenon.

17. Jan 17, 2012

### maverick_starstrider

So you're saying the fields AREN'T physical and that virtual particles ARE?! Virtual particles are a result of perturbative expansion, they're a mathematical artifact and there are many effects that such a scheme misses. As for fields I see no reason to say that fields aren't physical. In general I wouldn't take the notion of the exchange of messenger particles and such too seriously. If we could solve gaussian integrals with cubic terms you'd never have heard of a virtual particle. And if I remember the Higgs mechanism is indeed quite abstract, you need to give some Goldstone boson mass so you enforce some local gauge invariance and get some new massed field plus a "ghost" particle that you can transforms away or fix the gauge or something to get rid of. Admittedly my interest in QFT is from the condensed matter side and not the particle physics side. However, you get some term and from your Feynman calculus you get some perturbative expansion as a swapping of some new boson which is the Higgs and the result is the weak-force bosons have mass. Anyway, my point is it just comes in as another boson at that point.

18. Jan 17, 2012

### DaveC426913

Sorry JungleBeast, you are drawing conclusions you just have no business drawing.

1] Brian Greene, while I devour his works, does simplify things for the layperson. It will help you understand, but you can't take it as gospel such that you can start extrapolating your own conclusions based on it.
2] We don't understand the Higgs boson yet. But the idea is that, yes, the Higgs boson somehow gives matter its mass, and it is its mass from which inertia is derived.

19. Jan 17, 2012

### maverick_starstrider

I think the Higgs boson in understand perfectly well (by particle theorists). The issue is that the Standard Model doesn't fix masses, they're experimental constants

20. Jan 17, 2012

### DaveC426913

Well, considering we don't actually know it even exists, that's a pretty bold statement.

21. Jan 17, 2012

### junglebeast

That is a tricky question that I think nobody can really answer for sure. I have no definite opinions. What I meant is that there is a difference between understanding a physical process and understanding the math necessary to make predictions about that physical process under certain circumstances.

For example, consider discussing discussing an arbitrary physical process that is known to be an emergent phenomena from some low-level physics. If the low-level physics are explained in sufficient detail, then the mathematics of the emergent phenomena can be derived; in contrast, if one is given the mathematics that describe the emergent phenomena, it is not possible to conclusively infer what the actual underlying low-level physics was (because there could be many low-level physics that all result in the same approximate behavior at a larger scale).

Clearly, mass is not a thing that can be given like a present; it is a property. Thus, when it is said that "the Higgs mechanism gives mass to particles," it seems the only valid semantic interpretation of this statement is that the Higgs mechanism describes a lower level physics that is capable of describing mass as an emergent phenomena. In other words, mass is not a truly fundamental aspect of physics. If this is the case, then any theory that is formulated in terms of "mass" such as general relativity must be merely an approximate theory of the emergent phenomena that is modeled by the lower level physics. Thus, in discussions about this mechanism, any math that is based on mass becomes irrelevant to the discussion (except for fact-chacking of the underling mechanism behavior).

Dave, I have no agenda other than learning. I read, I study, I think, I listen, and yes I do math and make simulations in order to verify things when I can. I also ask questions when the mental model I have assimilated from various sources is incomplete or contradictory.

The only thing definite is the words on the page; these words are often ambiguous and to understand them means to attempt to draw some conclusion as to what the writer was intending to mean. This is true of all books, textbooks, and conversations that we may have. It was not my intention to make any inferences beyond those directly implied by the text.

It is also absolutely my business to ask questions based on the parts that seem confusing or contradictory. Asking questions is not something that should be only permitted by the "elite" few who pioneer a theory -- it is important that every person who wants to understand ask questions before believing in a theory, otherwise, it is a purely faith based, and that is religion not science.

It may be that I drew a conclusion that was not intended by the text. Such misinterpretations are inevitable, but that is not deserving of chastisement. I welcome corrections, that is why I am here asking.

22. Jan 17, 2012

### DaveC426913

It was not intended as a chastisement. You are clearly rational, inquisitive and critical. I simply meant the conclusions you were stating were extending beyond the reach of the postulates given.

23. Jan 17, 2012

### maverick_starstrider

Well this is going a little off topic but I work in condensed matter and I absolutely consider quasi-particles to be real and I don't see how it's any different in QFT. Even if a phonon IS a collective excitation of atomic nuclei it's still real. And in condensed matter the electron is screened by the background positive charge and it becomes a quasi-electron, in QFT a "real" electron is screened by the vacuum to remain a "real" electron with a renormalized charge, I don't really see the difference. I DON'T consider virtual particles real since they're just a perturbation scheme and they miss a lot of physics (and break a lot of physics). I consider them no more real then interpreting the second energy correction in a QM perturbation series:

$$\sum_{k \neq n} \frac{\langle k | H' | n \rangle}{E_k-E_n}$$

to mean "in a perturbative field the electron instantaneously undergoes all possible transition", it's just a mathematical artifact, it's not physical.

If gauge bosons are massless without the Higgs field and the experimentally observed massive when it's there then I'd say it's real.

24. Jan 17, 2012

### junglebeast

Just because an equation matches some observations doesn't mean that the equation represents something real. Newton's equations match a lot of observations but we know that they are not real -- they are merely approximation equations that describe emergent phenomena from a lower-level physics.

It is well known that any system involving an ocean of particles can be modeled more simplistically as a field at larger scales. This is the entire concept of CFD, where we successfully use field equations to model all sorts of things that we KNOW are not true fields, and yet get remarkably good accuracy (at the scale of measurement).

Furthermore, in CFD, there are at least 4 completely different perspectives that can be used to perform the simulation (field, particle, etc), and all of them will come up with the same outcomes. It would be a contradiction to say that all of these perspectives are real.

Moreover, we know that quantum field equations are only sometimes consistent with observation, because the field equations for the wavefunction do not provide any explanation for collapse into a delta function. You can brush this aside all you want, but the fact is, its an observation that does not agree with the field equations.

Last edited: Jan 17, 2012
25. Jan 18, 2012

### kurros

Of course you are correct, but your example is a very bad one. Let me punch you in the face, and then tell me again that F=ma isn't real. It is emergent from lower level physics, but it is madness to say that makes it not "real". Baseball is also emergent from fundamental physics, and perfectly real.

As above, the existence of multiple frameworks in which to analyse something does not make any of them more or less real. They can perfectly well be all real, within the domain of validity of each description.

If you want to be hard-nosed about it, the more valid thing to say is that every mathematical description of something is a model, and that is all. If it captures some aspect of reality accurately that is a handy thing, but it does not mean you can infer that nature "really works that way". Every model is "wrong". But of course in practice they work just fine for lots of things, despite only describing an ideal Platonian world if one is strict about ones philosophy. We could argue about this all day but it is not very helpful nor important for understanding the current problem I think.

Field equations by themselves do not tell the full story of a quantum field theory. The discontinuous process of wavefunction collapse, or whatever you may want to call it, is fully a part of the theory, and so far is 100% compatible with observations.

But I am not sure what your point is anymore. Philosophy aside, have we agreed that the Higgs field interacts with particles whether they are accelerating or not yet?

Last edited: Jan 18, 2012